Bait Preference of Free-Ranging Feral Swine for Delivery of a Novel Toxicant

Authors

Nathan P. Snow, Texas A&M University-KingsvilleFollow
Joseph M. Halseth, USDA/APHIS/ Wildlife Services, National Wildlife Research Center
Michael J. Lavelle, USDA/APHIS/WS National Wildlife Research CenterFollow
Thomas E. Hanson, USDA/APHIS/ Wildlife Services, National Wildlife Research Center
Chad R. Blass, USDA/APHIS/ Wildlife Services, National Wildlife Research Center
Justin A. Foster, Kerr Wildlife Management Area, Texas Parks and Wildlife Department
Simon T. Humphrys, Invasive Animals CRC, 33 Flemington St., Glenside, South Australia
Linton D. Staples, Invasive Animals CRC, 33 Flemington St., Glenside, South Australia
David G. Hewitt, Texas A&M University-KingsvilleFollow
Kurt C. VerCauteren, USDA-APHIS-Wildlife ServicesFollow

Document Type

Article

Date of this Version

2016

Citation

Snow NP, Halseth JM, Lavelle MJ, Hanson TE, Blass CR, Foster JA, et al. (2016) Bait Preference of Free-Ranging Feral Swine for Delivery of a Novel Toxicant. PLoS ONE 11(1): e0146712.

Comments

This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Abstract

Invasive feral swine (Sus scrofa) cause extensive damage to agricultural and wildlife resources throughout the United States. Development of sodium nitrite as a new, orally delivered toxicant is underway to provide an additional tool to curtail growth and expansion of feral swine populations. A micro-encapsulation coating around sodium nitrite is used to minimize detection by feral swine and maximize stability for the reactive molecule. To maximize uptake of this toxicant by feral swine, development a bait matrix is needed to 1) protect the micro-encapsulation coating so that sodium nitrite remains undetectable to feral swine, 2) achieve a high degree of acceptance by feral swine, and 3) be minimally appealing to non-target species. With these purposes, a field evaluation at 88 sites in south-central Texas was conducted using remote cameras to evaluate preferences by feral swine for several oil-based bait matrices including uncolored peanut paste, black-colored peanut paste, and peanut-based slurry mixed onto whole-kernel corn. These placebo baits were compared to a reference food, whole-kernel corn, known to be readily taken by feral swine (i.e., control). The amount of bait consumed by feral swine was also estimated using remote cameras and grid boards at 5 additional sites. On initial exposure, feral swine showed reduced visitations to the uncolored peanut paste and peanut slurry treatments. This reduced visitation subsided by the end of the treatment period, suggesting that feral swine needed time to accept these bait types. The black-colored peanut paste was visited equally to the control throughout the study, and enough of this matrix was consumed to deliver lethal doses of micro-encapsulated sodium nitrite to most feral swine during 1–2 feeding events. None of the treatment matrices reduced visitations by nontarget species, but feral swine dominated visitations for all matrices. It was concluded that black-colored peanut paste achieved satisfactory preference and consumption by feral swine, and no discernable preference by non-target species, compared to the other treatments.